1. Field of Invention
The invention relates generally to collapsible containers constructed of paperboard material, and more particularly to reinforcing the container during the manufacturing process and before the container is erected.
2. Description of Background Art
Historically the bulk packaging and transport of certain products has been accomplished through the use of octagon bulk containers. The length and width of these containers are such that they fit a 40xe2x80x3xc3x9748xe2x80x3 pallet with the depth of the container determined by the product packaged according to its weight. In addition, liner, medium and flute configuration of these containers is determined by the product being packaged, its weight and the resistance that the package must have to bulge and compression in order to maintain container integrity and shape during container transit. In addition to bulge resistance and in the case where containers are stacked two high during storage and transit, stacking compression required to support double stacking dictates the use of certain liner, medium and flute configurations.
By way of example, consider the use of octagon bulk containers in the poultry industry. This industry utilized basically two types of octagon bulk containers for shipment of chicken frames and bones and for shipment of mechanically deboned meat (MDM). The frames and bones left over from the processing of a chicken are typically shipped to an MDM processor. The bones are dumped into a xe2x80x9cgrinderxe2x80x9d and along with addition of salt and other additives, the end product, a thick flowable meat, is produced and packed into an octagon bulk container for shipping. This product is sold and shipped to companies producing hot dogs, bologna, and other meat items with the MDM meat used as a xe2x80x9cfillerxe2x80x9d.
The octagon container used for shipment of the MDM meat is sized, typically 36xe2x80x3-40xe2x80x3 deep, to accommodate 2,080 lbs. of this thick flowable meat. Because of the density of this product and the total weight in the bin, processors have typically placed 3-6 straps on the assembled container by hand, prior to filling. These straps are placed on the container to add resistance to bulge and to assist in preventing the container from rupturing at its glue joint, typically the place on a container subject to fail if not properly glued during manufacture. A fallacy in placing these straps exists, in that the strapping material typically used was not intended to resist bulge. Further, when applying the strap by hand, the friction seal typically used to connect the strapping material was not adequate for meeting the demands for preventing container rupture. In addition, the strap friction seal would break as well.
Further, by way of the example presented herein, the thick flowable meat (2,080 lbs.) has a tendency to have the products forming the flowable meat settle toward the bottom of the container, especially after being vibrated during transit. The greatest point of bulge would therefore occur within the bottom half of the container, thus pushing outward against container lower walls and straining the container glue joint. Typically container users, applying their own straps, are not aware that the straps should be placed at strategic intervals in order to provide the greatest resistance at the greatest points of bulge.
In order for the user to pre-apply their own straps to a container, typically they would have to unload a trailer truck of bulk containers shipped in the flat from container manufacturer and stage the unstrapped bulk in an area of their plant, a box room. Then an employee assembles a container in upright position, and using a hand tool, places 3-5 straps around the girth of an assembled container using whatever strapping material is available. The employee stages erected strapped containers in an area accessible to a packing line. The packing line comes to the staging area to secure container for filling.
It should also be noted that in the absence of a friction sealing hand tool, either metal or plastic buckles are typically used to secure the straps. In a food processing environment this introduces a potential hazard and contamination when one of the buckles inadvertently finds its way into the product.
The specification for a container typically requires a container having either triple wall (4 liners; 3 mediums) or laminated (double wall-to-double wall or double wall-to-single wall) construction. Use of these specifications afforded greater bulge resistance due to the actual thickness of combined corrugated materials. In either case, triple wall or laminated container construction, availability is limited due to a minimal amount of container plants having the manufacturing capability to produce containers to these specifications, and economically produce the container.
As described earlier, transport of frames and bones is accomplished through use of a octagon container. Performance requirements for this container are not as stringent as the above described container. When carrying 1200-1800 lbs. of wet frames and bones, which are not nearly as dense as various flowable meats, bulge is not as evident and in most cases straps do not have to be pre-applied for safer transit. What does remain critical to an even greater degree, however, is the performance of the glue joint. Unlike the previous container construction described and not having a plastic liner inserted in all cases as the previous product, the exposure to constant moisture from the bones, and oftentimes ice used during storage of the bones, requires that the glue joint be correctly manufactured. Should the glue joint on these containers rupture, an absolute mess is created that must literally be shoveled up by hand, leading to excess labor costs, disgruntled customers, disgruntled employees, and employees running the risk of injury.
The specifications for these containers typically require then relatively heavy liners and medium of double wall construction (3 liners; 2 mediums) to be impregnated with wax to resist the wet and moisture laden environment to which the container is subjected. Waxing precludes recycling and is neither ecologically nor economically sound.
Another requirement for each the previously described containers is the need for sesame tape. Approximately xe2x85x9cxe2x80x3 wide, this tape is laminated between the liners and medium of the container during the combining process on a corrugator at a box plant. The placement of 5-8 strands of this tape throughout the depth adds a degree of bulge resistance to the container. If, however, the container ruptures at the glue joint, which is the most common failure, sesame tape does nothing to add to the integrity and safe transit of the packed and filled container.
Although,  the octagon shape provides greater resistance to bulge over conventional rectangular or square containers, many octagonal containers do not meet the requirements demanded when used in the examples as  cited above. For example, resistance to bulging may occur when flaps on the container bottom do not properly fit or when flaps having typically xe2x85x9cxe2x80x3 wide slots, include slots with ragged edges due to dull slotting heads. Further, slots can vary in depth into the body of the container creating small openings or fall short of a score line causing tearing when folding. Both conditions weaken bulge resistance in corners of packed container.
It is an object of the invention to provide reinforcing of a paperboard container that will withstand the filling and handling when erected without the bulging and weakening that typically causes well known containers to fail, thus reducing user in-plant labor and material costs. It is further an object to provide a container that is reinforced with straps when in its flat condition. It is yet another object to automatically weld or heat seal the straps at strategic locations that are dependent on the product being packaged, the strapping positioned for providing the greatest degree of bulge resistance and compression value.
Further, it is an object to economically provide such reinforcement, thus eliminating the need for excess customer labor. It is anticipated that approximately 3-5 minutes per container typically required to friction seal straps by hand to an assembled container will be saved. The customer further saves by eliminating the need to purchase and inventory strapping material, hand equipment and maintenance parts. Areas previously used for container assembly, strapping and staging are also eliminated. With such objects met, the need for costly triple wall and laminated containers typically used because of the greater bulge resistance and stacking capability versus double wall will also be reduced. To this end, a reinforced paperboard container moveable from a flatted  flattened condition to an erected condition is provided which comprises panels formed from a flat blank of corrugated paperboard scored to form multiple parallel panels joined to one another along adjacent sides. Each panel having a flap extending from an end in prolongation of the panel, each panel being foldable at its juncture with its associated flap and adjacent flaps being separated from one another by a slit, whereby the panels and flaps may be folded inwardly to one another for forming a hollow body having generally vertical side walls and multiple straps for providing girth support to the container, each strap positioned outside the container wall in a supporting arrangement therewith, each strap providing horizontal girth support at longitudinally spaced locations along the panels forming the container side walls.
In a preferred embodiment of the invention, the flaps at the panel ends overlay one another for forming a bottom wall free of gaps between the flaps. The spaced locations of the straps have a greater separation from an adjacent lower location when the container is in its erected position thus providing greater support at lower portions of the container. At least eight panels are joined for forming an octagonal container which provides a container having a supporting strength in excess of a rectangular container having similar paperboard construction. Further, a glue joint extends along attached end panels and associated flaps.
It is further an object of the invention to reinforce the container in an automatic manner which is capable of a production output at least as efficient as containers typically strapped. It is further an object to provide an economical method that has the flexibility of automatically attaching straps at predetermined locations. The method for reinforcing a paperboard container moveable from a flattened condition to an erected condition includes the steps of forming elongated paperboard into multiple parallel panels joined to one another along adjacent sides, positioning a slit between panel end portions for forming a flap extending from each panel end, folding the paperboard for attaching paperboard longitudinally opposing ends, and attaching the opposing ends. This forms the paperboard into a flattened container having side wall panels and associated flaps held in a flattened condition for ease in shipping and handling the containers prior to their use. The present invention further includes the steps of conveying the flattened container for placing a strap around the container for providing girth support to the container when in an erected condition, attaching a first strap under tension around the flattened container at a first selected location on the panels, the first selected location at a first distance from the flaps, incrementally advancing the flattened container for attaching a second strap, and attaching a second strap at a second selected location on the panels, the second selected location being at a distance from the first strap greater than the first distance.
In a preferred method, the container is further advanced, and additional straps are attached at additional selected locations. Each location is at a greater separation distance from a previously attached strap location.
The reinforcing provided to the container provides significant bulge resistance and as a result lighter weight liner grade specifications are permitted which has the obvious effect of reduced cost to the user. By way of example, single wall containers with straps effectively replace the more expensive double wall containers without straps thereby, thus reducing customer cost and improving financial margins.